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bpo-35081: Make some _PyGC macros internal (GH-10507) 

* Move "GC" macros together:

  * PyObject_IS_GC()
  * _Py_AS_GC()
  * _PyObject_GC_IS_TRACKED()
  * _PyObject_GC_MAY_BE_TRACKED()

* Mark other GC macros as internal (#ifdef Py_BUILD_CORE):

  * _PyGCHead_NEXT(g), _PyGCHead_SET_NEXT(g, p)
  * _PyGCHead_PREV(g), _PyGCHead_SET_PREV(g, p)
  * _PyGCHead_FINALIZED(g), _PyGCHead_SET_FINALIZED(g)
  * _PyGC_FINALIZED(o), _PyGC_SET_FINALIZED(o)
  * _PyObject_GC_TRACK(o), _PyObject_GC_UNTRACK(o)
  * _PyGC_PREV_MASK_FINALIZED
  * _PyGC_PREV_MASK_COLLECTING
  * _PyGC_PREV_SHIFT
  * _PyGC_PREV_MASK

* Replace _PyGC_generation0 with _PyRuntime.gc.generation0
* _queuemodule.c: replace _PyObject_GC_UNTRACK()
  with with PyObject_GC_UnTrack()
* Document that  _PyObject_GC_TRACK() _PyObject_GC_UNTRACK() macros
  have been removed from the public C API.
This commit is contained in:
Victor Stinner 2018-11-13 12:52:18 +01:00 committed by GitHub
parent 0d12672b30
commit 1a6be91e6f
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
5 changed files with 52 additions and 38 deletions
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11
Doc/c-api/gcsupport.rst
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@ -61,11 +61,6 @@ Constructors for container types must conform to two rules:
end of the constructor.
.. c:function:: void _PyObject_GC_TRACK(PyObject *op)
A macro version of :c:func:`PyObject_GC_Track`. It should not be used for
extension modules.
Similarly, the deallocator for the object must conform to a similar pair of
rules:
@ -90,10 +85,10 @@ rules:
the fields used by the :c:member:`~PyTypeObject.tp_traverse` handler become invalid.
.. c:function:: void _PyObject_GC_UNTRACK(PyObject *op)
.. versionchanged:: 3.8
A macro version of :c:func:`PyObject_GC_UnTrack`. It should not be used for
extension modules.
The :c:func:`_PyObject_GC_TRACK` and :c:func:`_PyObject_GC_UNTRACK` macros
have been removed from the public C API.
The :c:member:`~PyTypeObject.tp_traverse` handler accepts a function parameter of this type:

2
Include/internal/pycore_pymem.h
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@ -147,8 +147,6 @@ struct _gc_runtime_state {
PyAPI_FUNC(void) _PyGC_Initialize(struct _gc_runtime_state *);
#define _PyGC_generation0 _PyRuntime.gc.generation0
/* Set the memory allocator of the specified domain to the default.
Save the old allocator into *old_alloc if it's non-NULL.

73
Include/objimpl.h
View File

@ -256,18 +256,18 @@ PyAPI_FUNC(Py_ssize_t) _PyGC_CollectIfEnabled(void);
/* Test if a type has a GC head */
#define PyType_IS_GC(t) PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)
/* Test if an object has a GC head */
#ifndef Py_LIMITED_API
#define PyObject_IS_GC(o) (PyType_IS_GC(Py_TYPE(o)) && \
(Py_TYPE(o)->tp_is_gc == NULL || Py_TYPE(o)->tp_is_gc(o)))
#endif
PyAPI_FUNC(PyVarObject *) _PyObject_GC_Resize(PyVarObject *, Py_ssize_t);
#define PyObject_GC_Resize(type, op, n) \
( (type *) _PyObject_GC_Resize((PyVarObject *)(op), (n)) )
/* GC information is stored BEFORE the object structure. */
#ifndef Py_LIMITED_API
/* Test if an object has a GC head */
#define PyObject_IS_GC(o) \
(PyType_IS_GC(Py_TYPE(o)) \
&& (Py_TYPE(o)->tp_is_gc == NULL || Py_TYPE(o)->tp_is_gc(o)))
/* GC information is stored BEFORE the object structure. */
typedef struct {
// Pointer to next object in the list.
// 0 means the object is not tracked
@ -278,10 +278,21 @@ typedef struct {
uintptr_t _gc_prev;
} PyGC_Head;
extern PyGC_Head *_PyGC_generation0;
#define _Py_AS_GC(o) ((PyGC_Head *)(o)-1)
/* True if the object is currently tracked by the GC. */
#define _PyObject_GC_IS_TRACKED(o) (_Py_AS_GC(o)->_gc_next != 0)
/* True if the object may be tracked by the GC in the future, or already is.
This can be useful to implement some optimizations. */
#define _PyObject_GC_MAY_BE_TRACKED(obj) \
(PyObject_IS_GC(obj) && \
(!PyTuple_CheckExact(obj) || _PyObject_GC_IS_TRACKED(obj)))
#endif
#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
/* Bit flags for _gc_prev */
/* Bit 0 is set when tp_finalize is called */
#define _PyGC_PREV_MASK_FINALIZED (1)
@ -304,20 +315,26 @@ extern PyGC_Head *_PyGC_generation0;
| ((uintptr_t)(p)); \
} while (0)
#define _PyGCHead_FINALIZED(g) (((g)->_gc_prev & _PyGC_PREV_MASK_FINALIZED) != 0)
#define _PyGCHead_SET_FINALIZED(g) ((g)->_gc_prev |= _PyGC_PREV_MASK_FINALIZED)
#define _PyGCHead_FINALIZED(g) \
(((g)->_gc_prev & _PyGC_PREV_MASK_FINALIZED) != 0)
#define _PyGCHead_SET_FINALIZED(g) \
((g)->_gc_prev |= _PyGC_PREV_MASK_FINALIZED)
#define _PyGC_FINALIZED(o) _PyGCHead_FINALIZED(_Py_AS_GC(o))
#define _PyGC_SET_FINALIZED(o) _PyGCHead_SET_FINALIZED(_Py_AS_GC(o))
#define _PyGC_FINALIZED(o) \
_PyGCHead_FINALIZED(_Py_AS_GC(o))
#define _PyGC_SET_FINALIZED(o) \
_PyGCHead_SET_FINALIZED(_Py_AS_GC(o))
/* Tell the GC to track this object.
*
* NB: While the object is tracked by the collector, it must be safe to call the
* ob_traverse method.
*
* Internal note: _PyGC_generation0->_gc_prev doesn't have any bit flags
* Internal note: _PyRuntime.gc.generation0->_gc_prev doesn't have any bit flags
* because it's not object header. So we don't use _PyGCHead_PREV() and
* _PyGCHead_SET_PREV() for it to avoid unnecessary bitwise operations.
*
* The PyObject_GC_Track() function is the public version of this macro.
*/
#define _PyObject_GC_TRACK(o) do { \
PyGC_Head *g = _Py_AS_GC(o); \
@ -325,17 +342,19 @@ extern PyGC_Head *_PyGC_generation0;
Py_FatalError("GC object already tracked"); \
} \
assert((g->_gc_prev & _PyGC_PREV_MASK_COLLECTING) == 0); \
PyGC_Head *last = (PyGC_Head*)(_PyGC_generation0->_gc_prev); \
PyGC_Head *last = (PyGC_Head*)(_PyRuntime.gc.generation0->_gc_prev); \
_PyGCHead_SET_NEXT(last, g); \
_PyGCHead_SET_PREV(g, last); \
_PyGCHead_SET_NEXT(g, _PyGC_generation0); \
_PyGC_generation0->_gc_prev = (uintptr_t)g; \
_PyGCHead_SET_NEXT(g, _PyRuntime.gc.generation0); \
_PyRuntime.gc.generation0->_gc_prev = (uintptr_t)g; \
} while (0);
/* Tell the GC to stop tracking this object.
*
* Internal note: This may be called while GC. So _PyGC_PREV_MASK_COLLECTING must
* be cleared. But _PyGC_PREV_MASK_FINALIZED bit is kept.
*
* The PyObject_GC_UnTrack() function is the public version of this macro.
*/
#define _PyObject_GC_UNTRACK(o) do { \
PyGC_Head *g = _Py_AS_GC(o); \
@ -347,16 +366,7 @@ extern PyGC_Head *_PyGC_generation0;
g->_gc_next = 0; \
g->_gc_prev &= _PyGC_PREV_MASK_FINALIZED; \
} while (0);
/* True if the object is currently tracked by the GC. */
#define _PyObject_GC_IS_TRACKED(o) (_Py_AS_GC(o)->_gc_next != 0)
/* True if the object may be tracked by the GC in the future, or already is.
This can be useful to implement some optimizations. */
#define _PyObject_GC_MAY_BE_TRACKED(obj) \
(PyObject_IS_GC(obj) && \
(!PyTuple_CheckExact(obj) || _PyObject_GC_IS_TRACKED(obj)))
#endif /* Py_LIMITED_API */
#endif /* defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN) */
#ifndef Py_LIMITED_API
PyAPI_FUNC(PyObject *) _PyObject_GC_Malloc(size_t size);
@ -364,8 +374,17 @@ PyAPI_FUNC(PyObject *) _PyObject_GC_Calloc(size_t size);
#endif /* !Py_LIMITED_API */
PyAPI_FUNC(PyObject *) _PyObject_GC_New(PyTypeObject *);
PyAPI_FUNC(PyVarObject *) _PyObject_GC_NewVar(PyTypeObject *, Py_ssize_t);
/* Tell the GC to track this object.
*
* See also private _PyObject_GC_TRACK() macro. */
PyAPI_FUNC(void) PyObject_GC_Track(void *);
/* Tell the GC to stop tracking this object.
*
* See also private _PyObject_GC_UNTRACK() macro. */
PyAPI_FUNC(void) PyObject_GC_UnTrack(void *);
PyAPI_FUNC(void) PyObject_GC_Del(void *);
#define PyObject_GC_New(type, typeobj) \

2
Misc/NEWS.d/next/C API/2018-11-13-12-13-04.bpo-35081.gFd85N.rst Normal file
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@ -0,0 +1,2 @@
The :c:func:`_PyObject_GC_TRACK` and :c:func:`_PyObject_GC_UNTRACK` macros
have been removed from the public C API.

2
Modules/_queuemodule.c
View File

@ -26,7 +26,7 @@ typedef struct {
static void
simplequeue_dealloc(simplequeueobject *self)
{
_PyObject_GC_UNTRACK(self);
PyObject_GC_UnTrack(self);
if (self->lock != NULL) {
/* Unlock the lock so it's safe to free it */
if (self->locked > 0)